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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Fam Zheng <famz@redhat.com>,
	qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Amit Shah <amit.shah@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 00/18] virtio-blk: Support "VIRTIO_CONFIG_S_NEEDS_RESET"
Date: Tue, 21 Apr 2015 08:58:30 +0200	[thread overview]
Message-ID: <20150421085619-mutt-send-email-mst@redhat.com> (raw)
In-Reply-To: <5535F3B4.20708@redhat.com>

On Tue, Apr 21, 2015 at 08:52:36AM +0200, Paolo Bonzini wrote:
> 
> 
> On 20/04/2015 22:34, Michael S. Tsirkin wrote:
> > On Mon, Apr 20, 2015 at 09:10:02PM +0200, Paolo Bonzini wrote:
> >>
> >>
> >> On 20/04/2015 19:36, Michael S. Tsirkin wrote:
> >>> At the implementation level, there's one big issue you seem to have
> >>> missed: DMA to invalid memory addresses causes a crash in memory core.
> >>> I'm not sure whether it makes sense to recover from virtio core bugs
> >>> when we can't recover from device bugs.
> >>
> >> What do you mean exactly?  DMA to invalid memory addresses causes
> >> address_space_map to return a "short read".
> >>
> >> Paolo
> > 
> > I mean, first of all, a bunch of virtio_XXX_phys calls.
> > These eventually call qemu_get_ram_ptr, which internally calls
> > qemu_get_ram_block and ramblock_ptr.
> > Both abort on errors.
> 
> address_space_translate and memory_access_size should ensure they don't.
> 
> Paolo

More comments in this code won't hurt.
It *looks* as if we assume we get a valid mr, and try to
access it.
In any case, no error is reported.

-- 
MST

WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Fam Zheng <famz@redhat.com>,
	qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Amit Shah <amit.shah@redhat.com>
Subject: Re: [PATCH 00/18] virtio-blk: Support "VIRTIO_CONFIG_S_NEEDS_RESET"
Date: Tue, 21 Apr 2015 08:58:30 +0200	[thread overview]
Message-ID: <20150421085619-mutt-send-email-mst@redhat.com> (raw)
In-Reply-To: <5535F3B4.20708@redhat.com>

On Tue, Apr 21, 2015 at 08:52:36AM +0200, Paolo Bonzini wrote:
> 
> 
> On 20/04/2015 22:34, Michael S. Tsirkin wrote:
> > On Mon, Apr 20, 2015 at 09:10:02PM +0200, Paolo Bonzini wrote:
> >>
> >>
> >> On 20/04/2015 19:36, Michael S. Tsirkin wrote:
> >>> At the implementation level, there's one big issue you seem to have
> >>> missed: DMA to invalid memory addresses causes a crash in memory core.
> >>> I'm not sure whether it makes sense to recover from virtio core bugs
> >>> when we can't recover from device bugs.
> >>
> >> What do you mean exactly?  DMA to invalid memory addresses causes
> >> address_space_map to return a "short read".
> >>
> >> Paolo
> > 
> > I mean, first of all, a bunch of virtio_XXX_phys calls.
> > These eventually call qemu_get_ram_ptr, which internally calls
> > qemu_get_ram_block and ramblock_ptr.
> > Both abort on errors.
> 
> address_space_translate and memory_access_size should ensure they don't.
> 
> Paolo

More comments in this code won't hurt.
It *looks* as if we assume we get a valid mr, and try to
access it.
In any case, no error is reported.

-- 
MST

  reply	other threads:[~2015-04-21  7:54 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-17  7:59 [Qemu-devel] [PATCH 00/18] virtio-blk: Support "VIRTIO_CONFIG_S_NEEDS_RESET" Fam Zheng
2015-04-17  7:59 ` [Qemu-devel] [PATCH 01/18] virtio: Return error from virtqueue_map_sg Fam Zheng
2015-04-17  7:59 ` [Qemu-devel] [PATCH 02/18] virtio: Return error from virtqueue_num_heads Fam Zheng
2015-04-17  7:59 ` [Qemu-devel] [PATCH 03/18] virtio: Return error from virtqueue_get_head Fam Zheng
2015-04-21  6:27   ` Michael S. Tsirkin
2015-04-17  7:59 ` [Qemu-devel] [PATCH 04/18] virtio: Return error from virtqueue_next_desc Fam Zheng
2015-04-21  6:37   ` Michael S. Tsirkin
2015-04-21  7:30     ` Fam Zheng
2015-04-21  9:56       ` Michael S. Tsirkin
2015-04-17  7:59 ` [Qemu-devel] [PATCH 05/18] virtio: Return error from virtqueue_get_avail_bytes Fam Zheng
2015-04-17  7:59 ` [Qemu-devel] [PATCH 06/18] virtio: Return error from virtqueue_pop Fam Zheng
2015-04-21  6:49   ` Michael S. Tsirkin
2015-04-21  7:24     ` Fam Zheng
2015-04-21  9:51       ` Michael S. Tsirkin
2015-04-17  7:59 ` [Qemu-devel] [PATCH 07/18] virtio: Return error from virtqueue_avail_bytes Fam Zheng
2015-04-17  7:59 ` [Qemu-devel] [PATCH 08/18] virtio: Return error from virtio_add_queue Fam Zheng
2015-04-17  7:59 ` [Qemu-devel] [PATCH 09/18] virtio: Return error from virtio_del_queue Fam Zheng
2015-04-17  7:59 ` [Qemu-devel] [PATCH 10/18] virtio: Add macro for VIRTIO_CONFIG_S_NEEDS_RESET Fam Zheng
2015-04-17  7:59 ` [Qemu-devel] [PATCH 11/18] virtio: Add "needs_reset" flag to virtio device Fam Zheng
2015-04-17  7:59 ` [Qemu-devel] [PATCH 12/18] virtio: Return -EINVAL if the vdev needs reset in virtqueue_pop Fam Zheng
2015-04-17  7:59 ` [Qemu-devel] [PATCH 13/18] virtio-blk: Graceful error handling of virtqueue_pop Fam Zheng
2015-04-17  7:59 ` [Qemu-devel] [PATCH 14/18] qtest: Add "QTEST_FILTER" to filter test cases Fam Zheng
2015-04-17  7:59 ` [Qemu-devel] [PATCH 15/18] qtest: virtio-blk: Extract "setup" for future reuse Fam Zheng
2015-04-17  7:59 ` [Qemu-devel] [PATCH 16/18] libqos: Add qvirtio_needs_reset Fam Zheng
2015-04-17  7:59 ` [Qemu-devel] [PATCH 17/18] qtest: Add test case for "needs reset" of virtio-blk Fam Zheng
2015-04-17  7:59 ` [Qemu-devel] [PATCH 18/18] qtest: virtio-blk: Suppress virtio error messages in "make check" Fam Zheng
2015-04-20 15:13 ` [Qemu-devel] [PATCH 00/18] virtio-blk: Support "VIRTIO_CONFIG_S_NEEDS_RESET" Cornelia Huck
2015-04-21  7:44   ` Fam Zheng
2015-04-21  8:04     ` Cornelia Huck
2015-04-21  8:38       ` Fam Zheng
2015-04-21  9:08         ` Cornelia Huck
2015-04-21  9:16           ` Fam Zheng
2015-04-21  9:55             ` Cornelia Huck
2015-04-21  9:59             ` Michael S. Tsirkin
2015-04-20 17:36 ` Michael S. Tsirkin
2015-04-20 17:36   ` Michael S. Tsirkin
2015-04-20 19:10   ` [Qemu-devel] " Paolo Bonzini
2015-04-20 19:10     ` Paolo Bonzini
2015-04-20 20:34     ` [Qemu-devel] " Michael S. Tsirkin
2015-04-20 20:34       ` Michael S. Tsirkin
2015-04-21  2:39       ` [Qemu-devel] " Fam Zheng
2015-04-21  2:39         ` Fam Zheng
2015-04-21  6:52       ` [Qemu-devel] " Paolo Bonzini
2015-04-21  6:52         ` Paolo Bonzini
2015-04-21  6:58         ` Michael S. Tsirkin [this message]
2015-04-21  6:58           ` Michael S. Tsirkin
2015-04-21  2:37   ` [Qemu-devel] " Fam Zheng
2015-04-21  2:37     ` Fam Zheng
2015-04-21  5:22     ` Michael S. Tsirkin
2015-04-21  5:22       ` Michael S. Tsirkin
2015-04-21  5:50       ` Fam Zheng
2015-04-21  5:50         ` Fam Zheng
2015-04-21  6:09         ` Michael S. Tsirkin
2015-04-21  6:09           ` Michael S. Tsirkin

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